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Mar. 6, 1923. L. W..PEASE DEVICE AND METHOD FOR MAKING STEREOSCOPIC X-RAY PICTURES Filed-June 6,v

1919 v2 sheets-sheet l lllllllllllllfilllill,

Maf. 6, 19.23.`

1,447,399 L. w. PEASE DEVICE AND METHOD FOR MAKING STEREOSCOPIC X-RAY PICTURES Filed June 6, *1919 2 sheets-sheet 2 @reiterated hier. i923. Y

err r rer l LOUES W. PE, 0F CHICA, ILQXS,

Device METHOD son i me sr Application med June t,

To all whom t concern Be it known that I, LOUIS W. Puse, a

citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Devices and Methods for Making Stereoscopic X-Ray Pictures, ot which the following 1s a specification, reference being had to the accompanying drawings, forming a part thereof.

The purpose of this invention is to provide a method or process and an apparatus or devices for producing and viewing a stereoscopic X-ray picture, that is, a picture which shall give the stereoscopic or relief effect without the use of an instrument for viewing it. It consists in the elements and features of construction of the device and in the steps of the process hereinafter described, asindicated in the claims.

ln the drawings:

Figure l is a diagrammatic view representing a section of a stereoscopic picture and screen by the use of which it is produced, in relation to the X-ray beams for producing it, the dimensions of the alternating lines or' areas of the picture being exaggerated for the purpose of delineating distinguishable ray lines in their relation to the diderent parts.

Figure 2 is a diagrammatic view show-- ing in a manner similar to Figure l, a pic' ture in relation to thel viewing screen and the positions of the eyes of the observer.

, Figure 3 is a plan view of a cassette for holding the necessary parts for producing a picture according to this invention, certain parts being broken away to disclose the interior.

Figure 4 is a detail edge elevation of a shifting device for shifting the screen.

Figure 5 is a section at the line 5 5 on Fi re 3.

igure 6 is a section at the line 6-6 on Figure 3. A

Figure 7 is a detail section of the necessary assemblage of elements for taking pictures with one iluorescent screen.

Figure ,8 is aA similar section with two fluorescent screens.

In looking at an opaque object against a white or luminous background, or with light thrown upon it from behind, so that the Vision is confined to or concentrated upon out lines, the vision which can be obtained with tures the accompanying drawings.

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one eye corresponds as to outline to the ordinary X-'ray picture, except as the X-ray picture also contains indication of thickness or density as hereinafter referred to. That is, such a view is equivalent to a shadow cast by the object focused on the retina of the eye. But with two eyes viewing an object under such circumstances there is obtained the impression of relief because of the two slightly different shadows of which the two eyes respectively receive impressions; and

.two such shadow pictures may be taken in a stereoscopic camera and viewed through a stereoscope to produce the same appearance of relief which the natural vision with two eyes aords under these circumstances.

The same value of relief or perspective is obtained by the present invention in the case of an X-ray picture, but this additional value, that inasmuch as an X-ray picture gives account, not only of outline, but also to a Valuable extent of thickness or density in the direction of the X-ray beam, two picltures taken with the direction of the beam changed by as much as the di'erence in the direction of vision of two eyes of an observer, will di'er just as the vision of the two eyes would differ, if the body were transparent, so that varying thickness could be observed by the eye. And just as two eyes looking at a transparent object of varying thickness, will see that variation of thickness and translate the impression into the surfaceconliguration which results from that varying thickness, so two X-ray picroduced by the beam projected from two d1rections, didering as much as the direction of vision of the two eyes would differ when arranged so that two eyes see, each the picture corresponding to its own direction of vision andnot the other picture, give the observer the impression, not only of outline relief, but also in a large measure of surface conguration due to varying thickness and density. That is, the observer is enabled to see the ob'ect as it would be seen by a normal vision i it were transparent; i. e., both in relief and with the front and back surfaces distinguishable in their configura'- tion at varying distance apart at different areas.

These results are obtained by apparatua for producing and viewing X-ray pictures which will now be described by reference to lll@ i, co

In the drawings, A rgpresents a portion Y ofa limb of whlch an -ray picture` is to lbe taken, B being the bone therein, and U a foreign substance to be located by means of the picture. D is a plate having on the surface toward the limb to` be pictured a sensitized film, d, adapted to receive an impression from the X-ray. E is a screen of aluminum which is substantially transparent to the X-ray. This screen has the surface which lies conti ous to the film grooved with a multip icity of narrow, closely-spaced grooves which are filled with lead, lead being opaque to the X-rays, so that said surface consists of alternating lineal areas, e1 and e2, of aluminum and lead respectively; that is, alternating lines or lineal areas, tranparent and opaque, respectively, to the -ray. Fand F1 repre- -sent the foci or emanating points of the X-ray beams, or two positions 'of the target of an'X-ray tube. T ese two positions are separated such a distance that the angle between the X-ray beams from them respectively at their incidence upon a given point of a surface ofthe film is substantially the angle between the. tworaysfrom that point to the two eyes of an observer at a normal viewing distance from thepicture. H is a frame or holder called'a cassette comprising the four sides, H1, H1, and H2, H8, and the aluminum screen plate, E, above described which constitutes a wall of thecassettathe four sides being permanently secured to 35 that face of the plate, E, in which are the lead-filled Vgrooves described, the securement of the side vbars to said wall plate bei-ng such as to exclude the passage of light rays between the plate and the side bars. The side bars, H1, H1, are rabbeted at h1 for engagement and guidance of the film or plate engaging slides, J, J, which are shown as integral with a bar, J1, making a ri id frame sliding' in said rabbets. members, J, J, may have right-angled notches, J2, J8, to afford accurate engage- `ment for film or plates of different dimensions, the ends of said slide members, J, J, making right angles with the side bars, H1, aording accurate seating for the widest plate to be accommodated in the cassette. L is a rock shaft or cam rod' journaledin the sides, H1, H1, of the cassette, and having toward their o posite ends flats, L1, L1, formed by cuttlng back the rock shaft or cam rod segmentally, thus making it afford cams for operating, as the shaft or rod is rocked, against the bar, J1, which is pro vided with extending lugs, 7'1, i1, exposed to this cam action. The rock shaft L., has a f lever arm, L2, outside the side bars, H1, for lrocking it between limits which are fixed by check pins, m, m, the angular-throw permitted being suilicient to carry the Hats,

I5 L1, L1, fmmposition abutting at against grooves.

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the co-operating protrusions, j1, of the bar, J, to a position entirely clearing sald rotrusions. The rocking of this cam ro or rock shaft serves to shift the film plate edgewise in direction crosswise of the lead lines of the screen, E, a distance substantially e ual to thewidth of the lead lines thereof, w ich is substantially equal to the width of the intervenin aluminum areas. At the opposite edge t e plate is engaged by afsecond bar, J1, also formed with end portions, J, having notches, J2, J3, in which the corners of the plate are held. A spring, N, secured to the side bar, H2, and acting upon the bar, J, yieldingly resists the thrust of the film or plate toward said side bar, andV follows it up when the cam rod or rock shaft, L, is rocked to bring its' flats, L1, into co-operationiwith the pro]ections, i1, ofthe bar, J1. The side bars, H1, H1, are grooved at 11.3,andthe bars, H2 and H3, are rabbeted to afford -a seat at h?, in the plane of the lower edge of the grooves, h3. C is a closurel plate adapted to lodge on said rabbets,

h1, and engages the grooves, H3, for enclosin the elements of the device already descri ed and excluding the luminous rays which might otherwise pass around the edges and efog the film. Two thrust pins,

R, R, are set through one ofthe side bars,

H1, from the outside into the groove, its, in

that bar, and springs R1, R1, secured to the bar, press said thrust pins inward into the The cover platel is applied by lodging twoopposite edges on the rabbets,

11.4, and thrusting the intervenin edge into the groove of one ofthe bars, H1, against the thrust pins until the opposite edge of the cover plate clears the opposite edge of the other bar, H1, so that the plate can be depressed at that'edge to engage the groove 11,3 in that bar into which it willbe thrust by the reaction of the thrust pins in the opposite bar.

For mak ng the stereoscopic X-ray pic- 110 ture, the cassette containing the plate or film with its sensitized side placed against the inner face, which-is the lead-lined-side, of the screen, E, will be mounted with the outer surface of the aluminum bottom plate, 115 E, against the surface of the limb of which the picture'is to be made, at the o posite side thereof from the source'of the ray beam; and an exposure is made with the beam v emanating from the focus, F. Then, with- 120 out moving the cassette from its position, thecam rod or rock shaft, L, is rocked to operate the cams and shift the film plate laterally,`-that is, crosswise of the lead- .lines and alternating aluminum lines of the 1,25 screen, E; and thereupon a second picture is taken by means of an X-ray beam emanating from F1. Each picture, it will be understood, consists of a` series of narrow and narrowly separated parallel areas or 130 strips, the strips which form one picture alternating on the film with those which form the other picture.

When this picture is viewed through a transparent screen, K, placed over the face of the'picture,- i. e., at the film side of the late,-with the light comin from .be-

hin the plate and with the sur ace of the screen, K, having the obscuration lines, k, at the side remote from the film, said screen may be adjusted laterally with respect to the lines until the obscuration lines are p'ositioned with respect to the alternating strips constituting the two pictures form@ upon the plate, so that one 'set of strips is hidden from one eye, at Il, as indicated in kFigure 2, and the other set of strips is hidden from the other eye at l2; whereupon each eye will see a picture substantially as the object presented wouldbe seen by that eye alone; and the two impressions thus made separately upon the two eyes will be translated as the impressions made upon the retinas of the two eyes would be translated it the observer were viewing the object directly; so that there will be the same eilect or impression of relief or perspective as would be'obtained in looking directly at the object. v

lt will be noticed that in order that the lead lling of the grooves in the plate, D, which form the lines on that plate opaque to the Yfray may not obstruct a greater width of one X-ray beam than'of the other, by reason oia the difference in direction from which the beams respectively are projected, it is important that the grooves be made V-sh'aped or narrowing' in width back from the surface, so that the lead filler becomes laterally beveled or tapered in cross section as shown in the drawings.

lt will also be observed that the width of the obscuration lines g and alternating transparentlines of the viewing screen, K, should theoretically diminish gradually from the-.middle part of that screen outward; that is, when the screen is wider than the distance assumed as the distance between the two eyes of the observer. For the purpose of locating the two X-ray foci fromwhich the two pictures are taken, an accurate stereoscopic eHect as to somuch of the picture as lies outside that width re# quires this progressive narrowing up .of the lines, because the surfacel of the viewing screen having the obscuration lines is necessarily at a suiiicient distance from the sur-l face of the picture viewed to permit the rays of light to pass out from behind these obscuration lines to one eye or the other. This distance, which is the thlckness of the glass screen itself, is almost negligible as to its eect in necessitating the graduation in width of said obscuration lines in the case of a picture only slightly wider than the unerase 'with which an ordinary distance between the eyes,that is, say up to four or five inches in width; but for perrect stereoscopic edect over the entire area of the picture more than three inches in width, this feature should be taken into account as described.

lt is well understood that the action ot the X-ray on the sensitized film is comparativelyslow, and that a sensible length of exposure is necessary for producing any effective X-ray picture. lt is also well understood that by the interposition of Ia fluor'- escent screen causing the production of luminous rays by the impact of the lil-rays, a picture is produced upon the film primarily by the luminous rays and by employing a 'Ill film highly sensitive to lummous rays, a

picture primarily caused by the X-rays may be taken with an approximation to the speed photographic negative may be produced.

Advantage may be taken of this well understood value of fluorescent screen by employing such screen in the apparatusdescribed and for the purpose described, the sensitized film being interposed between such uorescent screen and the lead-lined aluminum screen, as shown in Figure 7, in whh the fluorescent screen is indicated at For further. improving the effect in respect to the speed at which the picture may be taken, a second duorescent screen, Y, may be interposed at the opposite side of the film plate from the first screen, X, as shown in Figure 8. Theimpact of the X-ray passing through the film generates luminous rays upon the second ,fluorescent screen, Y, which are projected back in the direction of the inciting or generating X-ray, thereby making it act upon the film at the same point as the X-ray and intensifying the effect and correspondingly hastening the actinic action.

l claim:

1. The method ot making a stereoscopic X-ray picture which consists in making successively two exposures ,of a suitably-sensitized film plate to the action of two X-ray beams projected through and past the object to be pictured from two foci situated at such distance apart as to make the angle between them at their incidence upon any given point of the film substantially the angle between rays emanating from that point to the e es of an observer at a normal distance fbr viewing the picture, and interposing at the side of the film toward the X-ray beams a screen whose surface adjacent to the film has relatively fine lines alternatingly opaque and transparent to the `X-ray beams, and shifting relatively toeach rca lll

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going, in which the last mentioned step consists in. shifting the film 1 plate upon the screen plate between the two exposures.

3. lThe methodof making a stereoscopic X-ray picture which consists in making successively two exposures of a suitably sensitzed film l.plate to the action of two X-ray beams rojected through the Past the object to e pictured from two oci, situated at such distance apart as to make the angle tize sisting of a c osure plate and a sprin m terposed between said closure plate an' the between them at their incidence upon any given point of the film substantially the angle between rays emanatmg from that oint to the eyes of an observer at a norma' distance for viewin the f:ictuie and-interposing at the side o the m toward the X-ray beams, a, screen whose surface towardv the' lm has relatively fine lines alternately opaque and transparent to the -ray beam, interposing a fluorescent screen between said last mentioned screen and the film, and shifting relatively to each other the first mentioned screen and the film plate between the'two exposures.

4. .A` screen for use in producing stereosoopic X-ray pictures consisting of a plate made of material opaque to ordinary light rays and penetr ble by X-rays, such plate having on one sI rface alternating parallel grooves and spaces, the grooves being tapered in' cross-section, narrowing in width toward the opposite surface of the plate, and being lled with a substance opaque to the X-ray. l

5. A screen for use in producing stereoscopic X-ray pictures consisti of an aluminum platet having in one sur ace parallel grooves alternating with smooth areas, the grooves being filled with lead evenly to the lane of the surfaceof the plate, the grooves, ing narrowing in Gro-section from the y surface of the plate inward.

6;. An apparatus for taking stereoscopic X-ray pictures which comprlses a cassette having a wall plate of aluminum provided on its inner surface with parallel lead-filled grooves, sub-dividing that surface into alternating lines or narrow areas, res-pecfie .u 'transparent' and opaque 'to the X-ra and thereby constituting a screen forthe -ray beam; means for holding the sensitized plate snugly against said inner surface of the aluminum screen, and means for shifting the sensitized plate transversely of the lines on the aluminum screen.

7. In the construction defined in claim 6 fore oing, the means `forv holding the sensiplate a inst the screen plate, conlm plate for pressing the latter toward the screen plate, two opposite side bars of the cassette having inwardly-facing rooves adapted to receive two opposite e ges of the closure plate, and the other two opposite sides having rabbets formin shoulders in the plane of the inner si e of said grooves, whereby the cover plate engaged at two opposite edges in said grooves may be lodgedl at the other two opposite edges on said shoulder,.and spring means inthe bottom of one of the grooves for thrusting the opposite edge of the closure plate into the groove of the opposite side of the cassette.

8. In the construction'dened in claim 6 foregoing, the means for shiftin the lm plate comprising a spring at one side of the cassette against which one edge of the 'lm -plate lodges, a 'frame at the` opposite end of the cassette mounted for sliding in the other two sides of the cassette, adapteddfor engaging and thrusting against the edge of the film plate,'and a cam rod mounted for rockingin the cassette side bars having ycam elements engaging said sliding device for thrusting it toward the iilm plate to o May, 1919.

DR. LoUS W. PEASE. 

